Emmanuel Njukwe, Abdou Tenkouano, Delphine Amah, Kassim Sadik, Perez

Muchunguzi, Moses Nyine and Thomas Dubois

International Institute of Tropical Agriculture

TRAINING MANUAL TRAINING MANUAL TRAINING MANUAL TRAINING MANUAL

MMMMACROACROACROACRO----PROPAGATION PROPAGATION PROPAGATION PROPAGATION

OF BANANA AND PLANTAINOF BANANA AND PLANTAINOF BANANA AND PLANTAINOF BANANA AND PLANTAIN

2

1. INTRODUCTION 3

2. MACRO-PROPAGATION: AN OVERVIEW 4

STARTING MATERIAL 4

FIELD TECHNIQUES 4

DETACHED CORM TECHNIQUES 4

3. FIELD TECHNIQUES 5

FALSE DECAPITATION 5

Step 1. Removal of apical dominance 5

Step 2. Sucker detachment 5

COMPLETE DECAPITATION 6

Step 1. Removal of apical dominance 6

Step 2. Sucker detachment 6

4. DETACHED CORM TECHNIQUES 7

STEP 1. CONSTRUCTION OF PROPAGATORS 7

STEP 2. FILLING OF CHAMBERS 9

STEP 3. SELECTION OF SUCKERS 9

STEP 4. PREPARATION OF SUCKERS AND PLANTING 11

Whole corm 11

Split corm 12

Excised buds 13

Meristem drilling 14

PIF 14

STEP 5. PROPAGATOR MANAGEMENT 14

STEP 6. POTTING MIXTURE PREPARATION 15

STEP 7. ROOTING AND ACCLIMATIZATION 16

5. TIMELINE FOR DETACHED CORM MACRO-PROPAGATION 21

6. BUDGET FOR DETACHED CORM MACRO-PROPAGATION 22

3

1. INTRODUCTION

Plantain and banana are important staples and source of income for the smallholders that grow

them in the humid forest and mid-altitude agro-ecologies of sub-Saharan Africa. However, the

productivity and lifespan of banana and plantain fields have drastically reduced due to pest and

disease pressure. This problem is escalating because farmers usually depend on natural

regeneration of plants for the supply of planting materials, which are contaminated by pests and

diseases. Major pests are the banana weevil (Cosmopolites sordidus) and a complex of plant-

parasitic nematodes (Radopholus similis, Pratylenchus spp., Helicotylenchus multicinctus, and

Meloidogyne spp.). Major diseases are fusarium wilt, caused by Fusarium oxysporum f.sp.

cubense, and bacterial wilt, caused by Xanthomonas campestris pv. musacearum.

Banana and plantain can now be propagated aseptically in the laboratory through tissue culture

techniques. In vitro micro-propagation eliminates all sucker-transmitted pests and diseases, with

the exception viruses. However, tissue culture plants are relatively expensive and not readily

accessed by resource poor farmers, who constitute the biggest percentage of farmers in the

region.

The international Institute of Tropical Agriculture (IITA) has been investigating alternative means

for producing clean planting material. Macro-propagation is a relatively easy technique that is

carried out in a shed or even in the field. It consists of generating suckers from clean planting

material by removing the apical dominance. Macro-propagation can be classified into two

categories: field-based techniques, based on complete or partial decapitation, and detached

corm techniques, practiced in a shed.

This training manual aims to provide a step-by-step explanation of macro-propagation. A first

edition of this training manual was compiled by Emmanuel Njukwe, Abdou Tenkouano and

Delphine Amah for use among farmers in Cameroon. The current version of this training manual

was used for training farmer stakeholders from East and Central Africa during a week long

training session at IITA-Uganda.

4

2. MACRO-PROPAGATION: AN OVERVIEW

STARTING MATERIAL

It is very important that the starting material for macro-propagation is clean. Clean starting

material can be obtained in a variety of ways:

� through paring of suckers;

� through hot or boiling water treatment of suckers;

� through using tissue culture plants;

� through chemical treatment of the suckers.

FIELD TECHNIQUES

Two decapitation techniques exist. The two decapitation techniques involve stimulating lateral

bud production by destroying the active growing point (meristem) in the pseudostem. Both

techniques increase sprouting and sucker multiplication in the field. Using false decapitation, a

small hole is made in the pseudostem through which the meristem is destroyed. The foliage

remains physiologically active for about three months thereafter. Using complete decapitation,

the pseudostem is cut down, destroying the meristem.

DETACHED CORM TECHNIQUES

Detached corm techniques are currently promoted by IITA because of higher numbers of

resulting seedlings and growth uniformity of the seedlings. Seedlings obtained using detached

corm techniques are also less prone to stress once established in the field. Detached corm

techniques include:

� whole corm;

� split corm;

� excised buds;

� meristem-drilling;

� PIF (plantes issues de fragments de tiges) / plants resulting from stem fragments.

These techniques are simple and therefore easy-to-grasp, and cheap to establish with minimum

investment in construction of propagators and weaning facilities.

���� Of critical importance: start ‘clean’ !

5

3. FIELD TECHNIQUES

Both false decapitation and complete decapitation consist of the following steps:

� removal of apical dominance; � sucker detachment.

FALSE DECAPITATION

Step 1. Removal of apical dominance

A small hole (~ 5 cm in diameter) is cut in the pseudostem of six-month-old plants to destroy the

actively growing point (meristem). The hole is made at about 20 cm above the ground by

removing the central part of the plant. The hole should slightly slope downwards, so water and

plant sap collect in the hole, further killing the meristem. The plant is left to stand for at least one

month to allow sprouting.

Step 2. Sucker detachment

About four to seven suckers, depending on banana or plantain cultivar, will sprout three weeks

after removal of the apical dominance. Sprouted suckers are detached immediately once they

attain three to four leaves (usually when they measure 20-30 cm in height). Detached suckers

are transferred directly to the field.

Fig. 1. A hole made in the pseudostem

of banana plant.

6

COMPLETE DECAPITATION

Step 1. Removal of apical dominance

The pseudostem of a 6 month old plant is completely cut down at ground level. Emerging

suckers should not be cut. The meristem is destroyed by using a clean knife or machete and

removing the 5 cm diameter growing part in the middle of the pseudostem. Usually, the

meristem is soft and when hitting harder tissue (the corm), one can be sure the meristem is

destroyed. The corm is left to sprout for a month.

Step 2. Sucker detachment

About four to seven suckers, depending on banana or plantain cultivar, will sprout three weeks

after removal of the apical dominance. Sprouted suckers are detached immediately once they

attain three to four leaves (usually when they measure 20-30 cm in height). Detached suckers

are transferred directly to the field.

Fig. 2. After cutting down the entire pseudostem, the meristem is removed and the corm

is left to sprout.

Fig. 3. Suckers sprouting after a

complete decapitation.

7

4. DETACHED CORM TECHNIQUES

Using detached corm techniques, activities are carried out in propagators and weaning facilities.

Detached corms or buds are prepared for primary bud sprouting. Plantlets resulting from these

primary buds are subsequently prepared for secondary bud sprouting. Plantlets resulting from

these secondary buds are rooted. Finally, after an acclimatization period, they are ready for field

planting. After 12-18 weeks, using this technology, planting material can be multiplied ten-fold.

Using detached corm techniques, the following steps can be identified:

� construction of propagators;

� filling of propagators;

� selection of suckers;

� preparation of suckers and planting;

� propagator management;

� potting mixture preparation;

� rooting;

� acclimatization.

STEP 1. CONSTRUCTION OF PROPAGATORS

Propagators are used for sprouting of new seedlings and hardening of the subsequent sprouts.

Simple propagators can be constructed using fairly cheap materials, such as bamboo and

polythene sheets. Enterprising banana seedling producers could use iron rods and cast a

concrete floor. It is important that at least 50% shade is provided and that the fragile seedlings

are well-protected, by constructing a shade above the propagators. A convenient size for a

propagator is 1.5 (width) x 5.0 (length) x 1 (height) meter. Propagators should be kept clean and

completely covered with transparent polyethylene sheets. Humidity and temperature should be

high. The propagator compartments can be made using wood or bricks and should measure not

more than 0.5 m in height.

8

Fig. 4. Examples of propagators, with and without shades.

Fig. 5. Close-up of propagators.

9

STEP 2. FILLING OF CHAMBERS

Propagators are filled three quarter-full with steam-sterilized fine sawdust. Steam sterilization of

sawdust can be performed as follows using an oil drum. Iron bars are welded 20 cm above the

bottom of the drum on which an iron net is placed. The modified oil drum is then placed on

stands welded on the outside, usually about 20 cm above ground. An old potato bag can be

placed on top of the iron net to prevent sawdust from falling through the iron net. Water is

poured into the drum up to the height of the iron bars. After applying the sawdust into the drum,

the sawdust can be covered with old potato bags again. Heat is applied under the drum using

firewood and steam from the water sterilizes the sawdust. Steam is passed through this

construction for one hour.

STEP 3. SELECTION OF SUCKERS

Healthy sword or maiden suckers detached from plants that are in between flowering and

harvest can be used as source material, as well as corms of plants that are about to flower or

that are already harvested. Of critical importance is that the source material is pest- and disease

free. A maiden sucker is the most mature sucker on a stool and will give rise to the next crop

cycle. A sword sucker is a young sucker whose leaves are pointed like a sword. The decision

whether to use a sword sucker, a maiden sucker or corms depends on the type of detached

corm technique explained below. Prior to use, the pseudostem is cut off from the suckers.

Fig. 6. A propagator filled with steam-sterlized sawdust.

10

Roots are removed from a harvested sucker or corm, followed by a thorough wash to remove

plant and soil debris. The outer leaf sheaths are removed, one by one, 2 mm above the corm

and from the leaf base with a sharp knife. This will expose all the buds and/or the meristem. The

prepared material can be surface-sterilized for 20 min in a fungicide mixture. The buds are

scarified and the planting material is air dried for 24 hours.

Fig. 7. Sword suckers before paring

(right) and after paring (left).

Fig. 8. A whole corm.

Fig. 9. Suckers ready for cleaning.

11

STEP 4. PREPARATION OF SUCKERS AND PLANTING

Detached corm techniques include:

� whole corm;

� split corm;

� excised buds;

� meristem-drilling;

� PIF (plantes issues de fragments de tiges) / plants resulting from stem fragments.

Whole corm

Whole corm technique is applied to corms that are about to flower or that are already harvested.

The meristem is absent while buds are present. Propagation is by means of bud manipulation.

Roots are removed and the leaf sheets are cut away one by one, exposing the buds. A

fungicide can be applied. The corm is scarified at the top (by cutting an X) after which every

other observable bud is scarified. The entire corm is planted in the propagator. Corms are

planted at 30 cm intervals and covered fully with sawdust, and have to be well watered

immediately after planting.

Fig. 10. Cleaning, paring and antifungal treatment of corms.

12

Split corm

Split corm technique is applied to corms that are about to flower or that are already harvested.

The meristem is absent while buds are present. Propagation is by means of bud manipulation.

The whole corm is harvested and pared. Exposed buds on top are scarified. Leaf sheets do not

need to be removed. The corm is fragmented into two or more bits, depending on its size, and

planted in the chamber for buds to sprout. Prepared corm pieces are planted at 10 cm intervals

and covered with 2 cm of sawdust. The chamber is well watered immediately after planting.

Fig. 12. A corm with removed leaf sheets (left) and after scarification (right).

Fig. 11. Harvest of entire corm from the field and preparation for whole corm

technique.

13

Excised buds

Excised bud technique is applied to corms that are about to flower or that are already harvested.

The meristem is absent while buds are present. Propagation is by means of bud manipulation.

Buds are cut out from the corm in pieces of 50-100 g and planted in the propagator to sprout.

Buds are planted at 10 cm intervals and covered with 2 cm of sawdust. The chamber is well

watered immediately after planting.

Fig. 13. The corm is fragmented into

two or more bits depending on its

size.

Fig. 14. Sprouting suckers.

Fig. 15. Buds are cut out from the corm in pieces of 50-100 g. Buds can be planted

directly in plastic bags.

14

Meristem drilling

Meristem drilling is applied to a maiden sucker. The meristem and buds are present, but the

meristem is drilled. Propagation is by means of bud manipulation. The meristem is destroyed by

using a clean knife or machete and removing the 5 cm diameter growing part in the middle of

the pseudostem. Usually, the meristem is soft and when hitting harder tissue (the corm), one

can be sure the meristem is destroyed. The chamber is well watered immediately after planting.

PIF

PIF is applied to a sword sucker. The meristem is present while buds are absent. Propagation is

by means of meristem manipulation. The corm is pared and sterilized. The apical meristem is

scarified or fragmented longitudinally into 2 or 4 bits before planting. Fragments are planted with

the cut portion, which includes the meristem, facing up. The chamber is well watered

immediately after planting.

STEP 5. PROPAGATOR MANAGEMENT

During propagator management, it is important that a clean environment is maintained. Plants

should only be watered when necessary. If the plastic sheets are moist, no watering needs to be

done.

Depending on the cultivar, three to seven shoots arise from one piece of planting material.

Large shoots (usually obtained after three weeks) should be manipulated (scarified) to obtain

secondary plantlets as follows. Apical dominance is destroyed by cutting of the shoots and

making an X in the middle of the remaining corm. After another three weeks, each of these

shoots will give rise to three to seven shoots again.

Fig. 16. Primary shoots growing in a

propagator.

15

STEP 6. POTTING MIXTURE PREPARATION

Potting substrate can come from a wide variety of sources: top soil, sawdust, coffee husk, cocoa

husk, rice husk or oilpalm fiber. These substrates can be mixed in different proportions and

should be prepared in advance. Topsoil mixed with sawdust and composted organic matter at a

6: 3: 1 ratio is preferred. The potting substrate is steam-sterilized for 12 hours in a drum. An old

oil drum, modified by welding iron cross bars at about 20 cm from the bottom can be used for

steaming. Steam is prevented from escaping from the mixture when heating. After sterilization,

the potting substrate should be allowed to cool for 24 hours.

Fig. 17. Young plants (primary shoots) emerging from axillary buds on the corms.

Fig. 18. Steam-sterilized potting

substrate.

16

STEP 7. ROOTING AND ACCLIMATIZATION

After about 10 weeks, 10 to 50 secondary shoots will have emerged, each with two to three

small leaves. These plantlets are detached. Those that have roots go straight into the potting

mixture, using one plant per bag or cup. Those without roots are replanted in sawdust for 10

days prior to their movement to the potting mixture. It is important that a little portion of corm

remains attached to provide the plants with a nutrient reserve.

Fig. 19. Secondary shoots emerging from axillary buds on the corms (left). After they

attain two to three leaves (right), they are ready for rooting.

Fig. 20. Secondary shoots without

(right) and with roots (left).

Fig. 21. Sorting of secondary shoots

without and with roots.

17

Plantlets with roots are transferred in their plastic bags or cups to weaning facilities for

acclimatization. If plantlets are moved to distant nurseries for acclimatization, they should be

transported in humid transparent polythene bags. Acclimatization is ideal at 25-27oC and is

accomplished in shades 2 m in height for proper lighting and management. Plantlets being

acclimatized should be watered four times a week.

Fig. 22. Secondary shoots without roots are placed back in sawdust for 10 days.

18

After three to six weeks in the weaning facility, plants are ready for the field.

Fig. 23. Young plants placed in rooting substrate.

Fig. 24. Plantlets being acclimatized.

19

Fig. 25. Plantlets ready for field planting.

20

Fig. 26. Macropropagated plants in the field.

21

5. TIMELINE FOR DETACHED CORM MACRO-PROPAGATION Plants can be achieved ready for planting after 12-18 weeks.

Propagation stage Time period

Primary bud sprouting 3-5 weeks (depending on the climatic condition

and variety)

Secondary bud sprouting 2-3 weeks

Rooting of detached plantlets 2 weeks

Acclimatization 3-6 weeks

22

6. BUDGET FOR DETACHED CORM MACRO-PROPAGATION

This is a budget estimate for constructing a propagator comprised of four chambers with a total

capacity of 800 corms. These 800 corms can yield at least 8,000 plants in four months. The

propagator can last for more than five years

Item Unit cost (USD) Quantity Unit Total cost (USD)

Propagator (1.2 x 2 x1 m)

Transparent plastic sheets 6 8 sheet 48

Wood/scandle 6 50 scandle 300

Nails/zink nails 8 3 packet 24

Pins 4 2 packet 8

Roofing sheets 6 22 sheet 132

Transparent roofing sheets 5 18 sheet 90

Old roofing sheets 3 16 sheet 48

Subtotal propoagator 650

Materials

Old oil drums (200 L) 16 2 drum 32

Tags for identification 0.2 100 tag 20

Sawdust 2 100 bag 200

Plantain or banana corms 0.2 800 corm 160

Top soil 15 3 tipper 45

Poultry manure 2 50 bag 100

Polybags 0.04 8000 bag 320

Subtotal materials 877

Tools

Wheel barrow 12 1 barrow 12

Cutlass 7 1 cutlass 7

Digger 7 1 digger 7

Spade 7 1 spade 7

Big knives 1 2 knive 2

Small knives 0.5 2 knive 1

Large bowl 4 1 bowl 4

Watering cans 7 7 can 7

Fungicide 7 1 can 7

Protective clothes 20 1 suit 20

Subtotal tools 74

Labour (1 month)

Technician for construction 300 1 person 300

Skilled labour for preparation 100 2 person 200

Labour for Maintenance 50 4 person 200

Subtotal labour 700

Grand total 2301

23

MORE INFORMATION

For further information please contact IITA-Cameroon or IITA-Uganda.

IITA-Cameroon

PMB 208, Yaounde, Cameroon

Email: e.njukwe@cgiar.org

Tel: +237 2237434 and +237 2237522

IITA-Uganda

P.O. Box 7878, Plot 15, East Naguru Road, Upper Naguru, Kampala, Uganda

Email: t.dubois@cgiar.org

Phone: +256 75 2787808